Has this maturation innovator answered whisky distillers' prayers and reduced the angels' share?

Has this maturation innovator answered whisky distillers' prayers and reduced the angels' share?

Trials have shown that a device called the 'Scotch Bonnet' reduces alcohol evaporation during maturation, without negatively impacting flavour development

News | 20 Feb 2020

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A maturation innovation company thinks it has cracked the secret to minimising an expensive side effect of whisky maturation. The 'Scotch Bonnet' is a device fitted to casks that is designed to reduce the amount of spirit which evaporates from casks during their years of maturation.

Over the decades, many attempts have been made to negate the loss of alcohol to evaporation during maturation – commonly referred to as the 'angels' share'. These attempts have included 'tarring' casks to seal them and even wrapping barrels in polythene. However, it has been generally judged that these methods, while successfully halting the loss of alcohol, are failures due to their prevention of air exchange in and out of the cask. Both evaporation and oxidation are deemed by distillers to be two of the key processes of maturation, and exchange of air in and out of the cask is necessary for these processes to happen. Whiskies matured in casks wrapped in these ways are usually deemed to be immature for their age and exhibit poor flavour development — making the methods untenable.

However, the new 'Scotch Bonnet' device may be the answer to this conundrum. Ross Morrison, director of Scotch Bonnet and whisky industry veteran, spoke with various distillers about the bane of the angels' share and its direct impact on their profitability. He collaborated with friend Ken Hooker, owner of packaging firm Proteus, to create the Scotch Bonnet. Made from sustainably sourced, natural fibreboard, the 'bonnet' does not entirely eliminate evaporation from the barrel but has been shown to significantly decrease the loss of alcohol without negatively impacting the maturation process or the taste of the spirit.

After 42 months of testing on site in the warehouses of a distillery in Scotland, which came to an end in 2019, the team behind Scotch Bonnet have hailed the trial a success. They claim as much as 5.5kg of malt spirit was saved from evaporation over the period, which was subsequently used in blending.

The Scotch Bonnet is now patented worldwide and is being used by spirit distillers in Scotland, North America, Taiwan and the Caribbean.
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